Ensuring that all children are fully immunized against vaccine-preventable diseases is a critical public health issue. Child care centers (CCCs) and preschools are critical targets for efforts to increase the proportion of infants and young children who are fully immunized. The primary objective of this proposal is to rigorously examine current state, local government, and child care providers'efforts and barriers to ensuring that all enrolled children are up-to-date for required immunizations and to evaluate strategies to improve immunization coverage in child care centers and preschools. Specific Aim 1 will describe Utah state and local government activities to ensure compliance of CCCs, preschools, and Head Starts with state immunization requirements and identify government's barriers to ensuring compliance. Specific Aim 2 will describe CCC/preschool/Head Start staffs'knowledge, attitudes, and activities related to ensuring that all children are up-to-date for required immunizations and identify centers'barriers to ensuring up-to-date status. Specific Aim 3 will evaluate at least 3 strategies to ensure that all children enrolled in CCCs, preschools, and Head Starts are up-to-date for required immunizations. Aims 1 and 2 will guide the design of these strategies. Specific strategies proposed for Aim 3 are to: 1) design and pilot test an intervention to increase centers'use of the Utah State Immunization Information System (USIIS);2) design an online immunization education module and conduct a pilot randomized controlled trial to determine whether use of the module changes center providers'knowledge, attitudes, and activities and increases the proportion of children who are up-to-date for required immunizations;and 3) conduct a pilot randomized controlled trial to determine whether a quality improvement intervention implemented in CCCs, preschools, and Head Starts increases the proportion of children who are up-to-date for required immunizations. Utah is an excellent setting for the proposed research due to high IIS penetration;a mix of urban, rural, and frontier settings;and an increasingly diverse population in terms of race, ethnicity, and socioeconomic status. The strong collaborative relationship that exists between the University of Utah and Utah Department of Health will support the proposed aims and intervention strategies. In addition, child care providers will have an incentive to participate in the proposed research because Utah is implementing a new quality recognition system for CCCs that will include immunization measures. Finally, the collective research expertise of the investigators, including experience in conducting survey, quality improvement, school-based, and immunization policy and delivery research, will ensure the success of the proposed research. The proposed research will be a first step in identifying evidence-based, best practices that can be recommended by the CDC and other national organizations to state and local government agencies, CCCS, and preschools to ensure that children in child care settings are fully immunized.